XR Flight Operations Manual Version 3.0
Copyright 2006-2018 Douglas Beachy. All Rights Reserved.
28
NUMPAD.
Engage HOVER mode (hold altitude)
XR Airspeed Hold Shortcut Keys
S
Toggle
Airspeed Hold
on or off
CTRL-
Increase rate 25 m/s
CTRL-NUMPAD-
Decrease rate 25 m/s
Increase rate 5 m/s
NUMPAD-
Decrease rate 5 m/s
SHIFT-
Increase rate 1 m/s
SHIFT-NUMPAD-
Decrease rate 1 m/s
ALT-
Increase rate 0.1 m/s
ALT-NUMPAD-
Decrease rate 0.1 m/s
NUMPAD_ENTER
Hold current airspeed (also useful after NUMPAD* to hold a
lower speed
; i.e., “resume”
)
NUMPAD*
Reset rate to 0 m/s (i.e., "coast")
Center-of-Gravity Shifting
XR Vessels use center-of-gravity shifting and elevator trim in addition to RCS jets to
manage the ship’s pitch during reentry and atmospheric flight. If the
Attitude Hold
or
Descent Hold
autopilot is engaged the computer will control COG shifting
automatically. If you want to manage COG shifting yourself, ensure that the
Attitude
Hold
and
Descent Hold
autopilots are disengaged.
If
Attitude Hold
or
Descent Hold
is engaged, the flight computer will use COG shifting
in conjunction with elevator trim and RCS jets to maintain attitude, which allows the
ship to hold a stable reentry profile even under time acceleration. Also, it is
extremely efficient and uses very little RCS fuel. Attitude Hold also performs well in
atmospheric flight (for example, during SCRAM ascent). The ship is also very stable
when transitioning from conventional flight to hover while Descent Hold is engaged.
Note that the pumps that pump fuel forward or aft for COG shifting require a lot of
power, and therefore the APU must be active in order for them to operate. The APU
must be active in order for the elevator trim to operate as well. If the APU is offline
and
Attitude Hold
or
Descent Hold
is engaged in an atmosphere, by default the ship
will auto-start the APU so that COG shifting and elevator trim control can occur. If
you want to disable this feature, set
APUAutostartForCOGShift=0
in your
vessel’s
preference file.